Within any system, the forces of opposition cause strain and tug-of-war. For the common good, a settlement must be negotiated between the parties of opposing forces. A fundamental law of conduct is required so that the discords between different parties can be settled in an economic and civilized manner. Sometimes, lengthy skirmishes between parties with opposing goals can’t be avoided. Leadership by a diligent outsider, a presidential entity skillful in politics, can help to maintain the unity of system.
The blogbites.net is a blog about bites, and I’m talking about mastication, of course.
Performing an equilibration of an unbalanced bite with repeated Tscan-measurements is a sort of political science of sensory organs of occlusion. I fancy, the occlusion system is analogous to a kind of a house of parliament with a two party political system. There can be up to 32 members of parliament and each of these represent their own district of sensory organs. The sensors of the teeth involved send votes to the polling station, the ganglions and nuclei of the trigeminal nerve. As of yet, we only know that the afferents from a molar tooth periodontal ligament propagates directly, without synapsing, to the trigeminal motor ganglion. Maybe, the afferent pathways of the anterior teeth take a different route. However, what I see in a Tscan movie, I interpret, there are two different kinds of political interest-groups of teeth. The occlusal forces act as the votes do in a parliament sitting. The House of Parliament of Occlusion reacts very rapidly to the challenges of environment. A piece of seasonal delicacy, fruit and nut cake, is placed between the molars. A microsecond later, a parliamentary committee has made a decision to unleash the temporalis and masseter muscles. The mandible starts it upward movement. The soft dough part of the bolus between the molars is quickly squeezed, but suddenly, a piece of nut hits the occluding molar surfaces. A quick reappraisal of the situation is needed. The Back Tooth Working Class Party (BWCP, in short) – is adamant, the muscles should go on biting hard, or even harder. The members the Anterior Guidance Coalition (AGCP) can only watch by as the working class of the back teeth get all the votes and support from the sensor organs of their district.
However, nothing is constant in politics. The dental arch of the up-surging mandible hits the maxillary dental arch. The collision forces are partly absorbed by the food bolus, but a definite sharp contact is felt with the sensors of canine teeth of the working side. These unyielding, bold figures of the AGCP provide more sensory input, votes, than the back teeth do. The back teeth are not yet in actual tooth-to-tooth contact, but just wrapped in a sticky mass of fruit and nut cake. The results of the vote are unambiguous. According to the Universal Law of Jaw-closing the BWCP must restrain in its demands of masseter and temporalis activity. An agreement is made to slow down the mandible by the overwhelming majority of votes coming from the AGCP districts.
A microsecond later the masseter and temporalis muscles are ordered to rest, whereas the median pterygoid muscle starts pulling the mandible towards the maximum intercuspal position (MIP). This process, the mediotrusion, does not necessarily proceed smoothly. A piece of nut may get caught in a fossa of the opposing laterally gliding occlusal tooth surfaces. The emotions are heated in the district of BWCP. The piece of nut deflects slightly the path of the gliding mandible. In turn, the canine-canine contact is disengaged. Loss of votes for the AGCP ensues, and parliamentary orders execute, once again, the masseter and temporalis back to work. The piece of nut, that was stuck in a fossa, gets disintegrated. The canines make contact again, and the AGCP is once again triumphant. The glide of the mandible towards the MIP can continue.
There are situations where the parliamentary occlusal democracy is not working efficiently. The muscles can’t move the mandible. Sometimes when I test my patient’s ability to do the lateral excursion, the patient finds it impossible. The patient can’t do the lateral glide. The patient just makes tremendous efforts with his/her neck muscles bulging, nothing else happens except that after a while the patient sighs and admits that there must be something wrong with the brains…
There’s nothing wrong with the brains, nor with the brain stem nor with the ganglions of the trigeminal nerve. The nerves are working just right. There is a political crisis going on in the House of Parliament of Occlusion. Erosive, acidic diet and detrition have disfigured the shape of the mandibular canine. Formerly, in its time of glory, its tip was covered with bright enamel. It was the pinnacle member of the AGCP. The tip of canine has now turned into a flat plane of abraded, brown dentin. If it was only the esthetics! In MIP, the distal surface of the worn-down mandibular canine lies now in contact with the palatal cusp of the upper first premolar, a working class tooth. That means conflict! Believe me, class distinctions between neighboring teeth are sorely felt. A slightest lateral move of mandible would flare up traditional BWCP sentiments and make the masseter and temporalis go. The disfigured and humbled canine tooth tries in vain to disengage the masses of back tooth working class contacts. Conflicting parties refuse to work together, Instead, they orate their arguments in endless speeches. The movement of the jaw is stalled because both the parties are filibustering each their own causes. The arguments between BWCP and AGCP have paralyzed the House of Parliament of Occlusion.
Presidential interference is needed. A skilled dentist is an outsider, that is respected by both the parties of the Parliament of Occlusion. Here’s a tip for any dentist to identify this kind of crisis.
If your patient is unable to glide his/her jaw laterally, just place a blade of a hand instrument of matching thickness, it can be an amalgam carver, or as in the video below, the tips of pincers lying on the palatal aspect of the upper canine of the patient, teeth closed. The mandibular canine should be facing the other side of the instrument blade.
The laterally oriented force is now subjected only to the upper and lower canines. The instrument blade-mediated contact disengages the lateral force that otherwise would have been subjected to the palatal cusp of the upper first premolar. Miraculously, with the aid of an instrument blade held firmly between the canines the muscles are enabled to work effortlessly, the lateral excursion is restored. Your patient will be surprised to find out that you have cured his/her brain damage.
A dentist can stop the filibustering between the canine and first premolar by adding composite to the right places of the worn-down canine tooth. A dentist can be the president, that understands the core of the conflicts that are underway in the parliament of a patient’s occlusion. A president has the power to ascertain the stability of the democracy of occlusal forces.